Add a cc1 option to force disabling lifetime-markers emission from clang

Summary: This intended as a debugging/development flag only.

Differential Revision: https://reviews.llvm.org/D28385

llvm-svn: 291300

6 files changed, 12 insertions, 1 deletions

diff --git a/clang/include/clang/Driver/CC1Options.td b/clang/include/clang/Driver/CC1Options.td
index 2910b8521ba..ab296ebb9f6 100644
--- a/clang/include/clang/Driver/CC1Options.td
+++ b/clang/include/clang/Driver/CC1Options.td
@@ -167,6 +167,9 @@ def disable_llvm_passes : Flag<["-"], "disable-llvm-passes">,
            "frontend by not running any LLVM passes at all">;
 def disable_llvm_optzns : Flag<["-"], "disable-llvm-optzns">,
   Alias<disable_llvm_passes>;
+def disable_lifetimemarkers : Flag<["-"], "disable-lifetime-markers">,
+  HelpText<"Disable lifetime-markers emission even when optimizations are "
+           "enabled">;
 def disable_red_zone : Flag<["-"], "disable-red-zone">,
   HelpText<"Do not emit code that uses the red zone.">;
 def dwarf_column_info : Flag<["-"], "dwarf-column-info">,
diff --git a/clang/include/clang/Frontend/CodeGenOptions.def b/clang/include/clang/Frontend/CodeGenOptions.def
index 54c9f81265a..964a6cc2a00 100644
--- a/clang/include/clang/Frontend/CodeGenOptions.def
+++ b/clang/include/clang/Frontend/CodeGenOptions.def
@@ -52,6 +52,7 @@ CODEGENOPT(DisableGCov       , 1, 0) ///< Don't run the GCov pass, for testing.
 CODEGENOPT(DisableLLVMPasses , 1, 0) ///< Don't run any LLVM IR passes to get
                                      ///< the pristine IR generated by the
                                      ///< frontend.
+CODEGENOPT(DisableLifetimeMarkers, 1, 0) ///< Don't emit any lifetime markers
 CODEGENOPT(ExperimentalNewPassManager, 1, 0) ///< Enables the new, experimental
                                              ///< pass manager.
 CODEGENOPT(DisableRedZone    , 1, 0) ///< Set when -mno-red-zone is enabled.
diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp
index 8dd1623ee2c..aa08a454e4e 100644
--- a/clang/lib/CodeGen/BackendUtil.cpp
+++ b/clang/lib/CodeGen/BackendUtil.cpp
@@ -312,7 +312,8 @@ void EmitAssemblyHelper::CreatePasses(legacy::PassManager &MPM,
   // At O0 and O1 we only run the always inliner which is more efficient. At
   // higher optimization levels we run the normal inliner.
   if (CodeGenOpts.OptimizationLevel <= 1) {
-    bool InsertLifetimeIntrinsics = CodeGenOpts.OptimizationLevel != 0;
+    bool InsertLifetimeIntrinsics = (CodeGenOpts.OptimizationLevel != 0 &&
+                                     !CodeGenOpts.DisableLifetimeMarkers);
     PMBuilder.Inliner = createAlwaysInlinerLegacyPass(InsertLifetimeIntrinsics);
   } else {
     PMBuilder.Inliner = createFunctionInliningPass(
diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index 7cab13de923..137c69420dd 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -42,6 +42,9 @@ using namespace CodeGen;
 /// markers.
 static bool shouldEmitLifetimeMarkers(const CodeGenOptions &CGOpts,
                                       const LangOptions &LangOpts) {
+  if (CGOpts.DisableLifetimeMarkers)
+    return false;
+
   // Asan uses markers for use-after-scope checks.
   if (CGOpts.SanitizeAddressUseAfterScope)
     return true;
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 93bbcc42da1..36f6b0a5111 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -520,6 +520,7 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
     Opts.EmitLLVMUseLists = A->getOption().getID() == OPT_emit_llvm_uselists;
 
   Opts.DisableLLVMPasses = Args.hasArg(OPT_disable_llvm_passes);
+  Opts.DisableLifetimeMarkers = Args.hasArg(OPT_disable_lifetimemarkers);
   Opts.DisableRedZone = Args.hasArg(OPT_disable_red_zone);
   Opts.ForbidGuardVariables = Args.hasArg(OPT_fforbid_guard_variables);
   Opts.UseRegisterSizedBitfieldAccess = Args.hasArg(
diff --git a/clang/test/CodeGen/lifetime2.c b/clang/test/CodeGen/lifetime2.c
index 0d22282fdd4..4374b3c279c 100644
--- a/clang/test/CodeGen/lifetime2.c
+++ b/clang/test/CodeGen/lifetime2.c
@@ -1,4 +1,6 @@
 // RUN: %clang -S -emit-llvm -o - -O2 %s | FileCheck %s -check-prefixes=CHECK,O2
+// RUN: %clang -S -emit-llvm -o - -O2 -Xclang -disable-lifetime-markers %s \
+// RUN:       | FileCheck %s -check-prefixes=CHECK,O0
 // RUN: %clang -S -emit-llvm -o - -O0 %s | FileCheck %s -check-prefixes=CHECK,O0
 
 extern int bar(char *A, int n);